Link insertion, also known as dynamic keyword insertion, personalizes PPC ads by automatically inserting a user's search term (like-best running shoes for women) into your ad copy, making them more relevant and likely to be clicked. This improves click-through rates, potentially lowers your cost per click, and even boosts your ad quality score with search engines. By strategically using relevant keywords and ensuring consistent landing pages, link insertion can significantly enhance your PPC advertising effectiveness.